The health care provider will clean and shave the area of the body (usually near the groin) and then place a needle into the artery. A local numbing medicine will be put on the area before the needle is inserted.

Once the needle is in the proper position, a thin wire passes through it. The needle is taken out, and a long, narrow, flexible tube called a catheter is put in its place. An instrument called a fluoroscope sends special x-ray images of the body to a TV monitor. The images help the radiologist guide the catheter into the right position. The catheter runs over the wire and is pushed up into the main blood vessels of the pelvis to the aorta (the main blood vessel running down from the heart to the lower body).

The test uses a special dye (called "contrast medium") to help the arteries show up better on the x-ray. The blood vessels of the kidneys are hard to see with ordinary x-rays. The dye flows through the catheter into the kidney artery.

X-ray images are taken as the dye moves through the blood vessels. Saline (sterile salt water) containing a blood thinner may also be sent through the catheter to keep blood in the area from clotting.

A computer may be used to "subtract" out the bones and tissues in the area so that only the blood vessels filled with the dye can be seen. This is called digital subtraction angiography (DSI).

The catheter is removed after the x-rays are taken. Pressure is immediately applied to the area for 10 to 15 minutes or more to stop the bleeding. After that time, the area is checked and a bandage is applied. You should keep your leg straight for 6 hours after the procedure.

How to prepare for the test:

Tell the health care provider if:

You are pregnant

You have ever had any bleeding problems

You currently take blood thinners, including daily aspirin

You ever had any allergic reactions , especially those related to x-ray contrast material or iodine substances

You must sign a consent form. Do not eat or drink anything for 8 hours before the test. You will be given a hospital gown to wear and asked to remove all jewelry. You may be given a sedative or pain pill before the procedure.

How the test will feel:

The x-ray table is hard and cold. You may wish to ask for a blanket or pillow.

Some people feel a sting when the anesthetic (numbing medicine) is given. You will feel a brief, sharp pain as the catheter is inserted. There is a feeling of pressure as the catheter is moved into the body.

Some people feel a warm or burning sensation when the dye is injected. There may be slight tenderness and bruising at the site of the injection after the test.

Why the test is performed:

The test is done to look at the blood vessels that feed the kidney. It may show:

There is low radiation exposure. However, most experts feel that the risk related to most x-rays is smaller than other risks we take every day, such as driving in cars. Pregnant women and children are more sensitive to the risks related to x-rays.

Special considerations:

The test should NOT be done if you are pregnant or tend to bleed.

Magnetic resonance angiography can be done on those who cannot have a renal arteriography exam. MRA is noninvasive, and can provide similar imaging of the kidney arteries.